Line width roughness (LWR) control is a critical issue in extreme ultraviolet lithography (EUVL). The
difficulty of controlling LWR and the need to minimize it have grown as the sensitivity of materials and
resolution in the resist patterning process has improved. Another critical feature that has become difficult to
control in EUVL and 22nm half-pitch systems is pattern collapse. The increase of aspect ratio that comes from
further scaling promotes the onset of pattern collapse. Both pattern collapse and LWR are easily observed in
EUVL and leading-edge ArF immersion lithography.
This paper will demonstrate recent gains in LWR control in leading EUV films using track-based processes,
etch-based improvements, and the results of combined techniques. Also the use of a newly developed EUV-specific
FIRM™ rinse chemistry to reduce pattern collapse will be discussed along with future development
activities and industry requirements for both LWR and pattern collapse.